Lithium occurs widely throughout the Earth's crust, its average concentration is around 20 parts per million. This concentration compares with that of other valuable metals such as cobalt, but is much lower than iron and aluminium, yet it is far more abundant than the precious metals gold and platinum. But the metal is widely dispersed and high-grade deposits appear to be uncommon and generally small, so known economic resources may be inadequate to meet requirements for applications where its use is likely to grow substantially over coming years and decades, notably batteries.
Lithium batteries even now allow electricity to be stored in usefully large quantities per unit of battery weight: at least 150 Watt-hours per kilogram (Wh/kg), preferably 250 Wh/kg, with perhaps 1,500 Wh/kg possible in the longer term. Such storage intensities will allow electricity to penetrate road transport markets hitherto entirely dominated by petroleum fuels, and accelerate the development and deployment of electricity generation systems utilising the inherently intermittent renewable energy forms: wind and sun.
Recovering lithium from seawater is likely to remain prohibitively expensive because of its very low concentrations (less than 0.2 parts per million by weight), even though the total quantity in seawater vastly exceeds any foreseeable demands, at more than 200 billion tonnes of the metal.
Economic supplies of the lithium chemicals needed to make lithium batteries are currently dominated by brines from South American salt lakes (salars) in the so-called ‘Lithium Triangle’ that extends across areas of Argentina, Bolivia and Chile. However, security of supply from these salars is jeopardised by sovereign risk issues, environmental challenges, and doubts over just how much economically recoverable lithium is contained in these salars.
Lithium is also recovered from certain hard-rock silicate minerals. However, until recently, there was little interest in exploring for hard-rock lithium mineral deposits, firstly because perceptions have been that there was an abundance of lithium in the salars of the Lithium Triangle; and, secondly, because current hard-rock lithium ore refining processes (largely unchanged since before World War II) are expensive, complicated, hazardous and environmentally challenging.
With the benefit of a markedly superior process, the world's hard-rock lithium resources may be developed to the benefit of battery manufacturers, affording them greater confidence that lithium supplies for batteries will be secure over the longer term, and met at lower overall cost, than otherwise.
A reference herein to the background or prior art does not constitute an admission that such art forms part of the common and/or general knowledge of a person of ordinary skill in the art. Such a reference is not intended in any way to limit the process and system as set forth herein.